Prologue:
There are always two sides in life; living and death. Everyone wants to live, because that would mean you're enjoying the perks of what is available on Earth. But with death, you won't have to go anywhere except Heaven or hell. You can't experience love, appreciation, and all the good things you indulged in while living.
But death puts an end to all your suffering and pain. And that's the best part about it.
It's a good thing people like us don't die. We never get harmed or get involved in dangerous acts that you humans partake. We're creatures who have roamed your world for thousands of years, searching for the girl who will stop the destruction that is about to happen.
What are we called? It's a secret.